The presently-used systems for producing oil and gas oftentimes involves monitoring a number of functions at a plurality of locations. As an example, safety or control devices may close a valve, thereby barring fluid passage in a productive line, if the line or supply pressure is greater or lesser than specified parameters. In the situation wherein several system functions are being monitored and a mal-function occurs with respect to one of them, resulting in systems shut down, it is highly desirable to be able to quickly determine the precide mal-function. This invention allows such determination.